Apparatus for treating wells



2 Sheets-Sheet l x hh.

L A.. MILLER Y APPARATUS FOR TREATING WELLS Aug. 25, 1953- Filed Dec..5. 1946 IRA A.v MILLER INVENTOR.'

BY Z3/M Arme/vn Patented Aug. 25, 1953 APPARATUS FOR. TREATING WELLS IraA. Miller, Dallas, Ilex., assignor to Otis AEngineering Corporation,Dallas, Tex., a corporation of Texas Application December 3, 1946SeralNo. 713,695

(Cl. 16S-2) 8 Claims.

, -This-` invention relates to new and useful improvements in apparatus`for treating wells.

modern oil and `gas well production practice, it is becoming morefrequently customary to install packers between the well ow conductor ortubing and thebore of the well or the Well casing, and tovinsert loadingfluids, such as columns of water` or mud or the like, in the eannular-space between the well .tubing and casing above the packers tocounterbalance ory exceed .the upwardgforce exerted against such packersby the highbottom hole uid pressures, and to prevent application of suchhigh fluid pressures-to thewell casing,ltubing and surface connections.The pressure load of the column ofloading fluids the annular space isfrequently considerably in excess of the well formation pressure, and 1the differentiall pressure increases as the -well formation pressuredeclines. It would be possible, if an adequatelyl large and heavy`quantityl Yof loading fluids were introduced into the annu- V`larspace,to utilize these loading fluids to kill the well by providingysuitable means just .above the packer for establishing communicationbe- -tween the-annular space and the bore of the ow conductor, wherebythe loading fluids couldvbe admitted to the flow conductor where theywould Vserveto more than counterbalance the natural Aformation pressureand/prevent flow from the Well.

It is, therefore, an importantobject -of this 4invention to provide a;novel apparatus for treating :a ,Well to festablishcommunication`between VVVthe annularspace exteriorly ,ofl arwell-flow con-Aductorabove a packer and the bore of the cono ductor'for admittingloading fluidsffrom such annular space to the-conductor and the` wellfor- 1 mation with which such conductor` communicates to kill the well.

It is also .-an object of the invention tov provide such anappaiatus-for/treating awell ywherein lthe establishing ofcommunicationbetweenthe .annular space and the bore of the conductoriseiected withoutapplication of-extraneous pressure, without moving orrotating the conductor and without a flexibleline in the conductor Vatthe time the communication is established.

A further object of the invention isV to provide an: improved apparatusfor treatinga wel1, hav inga ow conductor therein witha packer forsealing off the 'annular space exteriorlyfofthe conductor, whereinaloading fluid is introduced into andL stored inthe. annular spaceabovexthe packer insufficient volume and oflsufficient consistency-tokill-'or preventffflow from thewelllwhen `2 suchloadingfluid isalsoadmitted tothe 4bore of the iiow conductor, the loading iiuidgbeingexcluded from said flow conductor until it is ,de

`sired to kill the well, whereuponcommunication is established betweenthe annular space andthe kbore of theconductor at a point above thepacker by means utilizinguid pressure present inthe wellLandtheloadingviiuid is permitted Lto enter the` conductorto kill the well.

Another object of the invention-is to provide Va novel circulatingdevice 'for a'well'ovw con- .flow conductor abovfefrthe` packer andthebore of Vvide a circulating device, of the character `described, whereintheclosure means for the circulating ports is designed towithstand-substantially as `great a pressure'from-without the flowconductor as the ow conductoritself will stand, whereby the normaluseand the functioning of the owconductor isnotaffected or decreased' bythe provisionA ofthe circulating device therein.

A further object of the invention is to provide a circulating vdeviceofthe character described having a plug for'closingfthe circulation portwhich is reinforced against displacement inwardly, and wherein thereinforcingr means isrremovvable to permit the closure plug to Vbedisplaced from said circulation port.

A particularly important object vof the'invention is to providesin acirculating device, of the Vcharacter described, `a reinforcing sleeveforgprewell to, a. closure, memberadaptedlfbe lowered 3 or dropped intothe well conductor and anchored in said sleeve, whereby the closure plugmay be displaced from closing position by uid pressure to establish apath of communication between the exterior and interior of the flowconductor.

A still further object of the invention is to DIO- vide, in a well flowconductor having a packer connected therewith, a circulating devicewhich may be opened by the applicationof the well uid pressure to aremovable plug lowered or dropped into the well flow conductor andreleasably connected to a removable reinforcing sleeve in thecirculating device, whereby circulation may be established between thebore of the well ow conductor and the annular space above the packerwithout moving the well ow conductor.

Additional objects and advantages of the i11- vention will be readilyapparent from a reading of the following description of a deviceconstructed in accordance with the invention, and reference to theaccompanying drawings thereof, wherein:

Figure 1 is a schematic view of a well having loading fluid therein, andshowing a packer and circulating device being installed in said well.

Figure 2 is a view similar to Figure l showing the packer in sealingposition and the loading fluid stored in the annular space between theflow conductor and well casing above the packer,

Figure 3 is a view similar to Figure 1 showing the circulating deviceopened and the loading fluid admitted to the bore of the flow conductorto prevent ow from the well producing formation,

Figure 4 is a transverse vertical sectional view of a circulation deviceconstructed in accordance with the invention, and showing the sameconnected in a well ow conductor,

Figure 5 is a view, similar to Figure l, showing the removable closuremember releasably anchored in the reinforcing sleeve preparatory topening the circulating device, and

VFigure 6 is a transverse vertical sectional view of the circulatingdevice in opened position.

In the drawings, the numeral I0 designates an elongate tubular housinghaving an axial bore Il. External screw threads I2 are provided at eachend of the housing, whereby it may be connected in a well now conductoror tubing string T by means of the usual couplings C. The housing isformed with an external annular ange I3, and one or more laterallyextending or radial openings or ports I4 are formed centrallyof theange. The outer portion of each port is enlarged in diameter, whereby anoutwardly facing annular shoulder I is provided in the mid-portion ofthe port.

A closure member 0r plug I6, having an external annular flange I7 formedintegral with its outer end, is positioned within the port to close thesame. The flange I'I on the plug engages and is pressed tightly againstthe outwardly facing shoulder I5 in the port by means of a clampingbushing I8 which is screw-threaded into the enlarged portion of the boreof the port, so that the flange is clamped securely in place in the Dortbetween the shoulder I5 and the inner end 0f the bushing. The bore ofthe bushing is preferably slightly larger than theexternal diameter ofthe plug I6 and the reduced inner portion of the port I4.

The lower portion of the bore of the housing I0 is reduced in diameter,ywhereby an upwardly facing seat I9 is formed in said bore at a pointbelow the lateral ports I4, and a reinforcing sleeve 2B is slidablyinserted into the upper portion of the bore of the housing and supportedupon the seat. The bore 2I of the reinforcing sleeve is of substantiallythe same dimension as the reduced lower portion of the bore of thehousing l0, whereby the flow of fluids through the housing is notrestricted by the reinforcing sleeve.

One or more lateral recesses 22 are formed in the external surface ofthe reinforcing sleeve, being so positioned that they align With thelateral ports I4 in the housing. Each recess 22 is of a sizecorresponding to the size of the inner reduced portion of the port I4,and the inner end of the plug I6 projects into such recess when thesleeve is in place in the housing, as clearly shown in Figures 4 and 5.The recesses 22 extend only a short distance into the wall of thereinforcing sleeve, whereby the wall of the sleeve supports the plugagainst inward displacement from the port I4. The engagement yof theinner end of the plug with the recess 22 provides a frangible orshearable means releasably retaining the reinforcing sleeve in positionin the housing.

Gbviously, since the flange Il is clamped Securely between the shoulderI5 and the bushing I8 and the inner end of the plug I6 is in engagementwith the reinforcing sleeve 2t, any pressure uid acting upon the plugfrom exteriorly of the housing will only urge the plug more tightlyagainst the reinforcing sleeve, and displacement of the plug inwardly ofthe port is thus positively prevented. However, if the reinforcingsleeve 20 is removed from within the bore of the housing, theapplication of a sufcient pressure difierential against the plug fromexteriorly of the housing will force the plug inwardly of the port andwill thus shear or break ofi' that part of the ange ii extending beyondthe diameter of the reduced inner portion of the bore of the port andthe plug will be displaced completely inwardly from the port to permitthe now of fluids therethrough.

By varying the thickness of the iiange on the plug or the material fromwhich the plug is made, or both, it will be seen that the pressuredifferential required to be exerted across the plug to displace the samemay be controlled and predetermined. Therefore, the plug may be securedwithin the port so as to be displaceable at various predetermined iiuidpressure differentials after the reinforcing sleeve is removed.

In the majority of installations in which the circulating device isused, and in practicing the method herein set forth, the excess pressurewill normally be from exterorly of the housing. It is preferable,therefore, that the plug be made of a relatively low shear strengthmaterial, such as lead or copper, since the reinforcing sleeve provideadequate support to prevent inward displacement of the plug from theport. Also, it is preferable that the plug be made of a relatively softmaterial in order that a iiuid tight seal may be obtained to close theport. The seal is secured by the compression of the ange of the plugbetween the bushing I8 and the outwardly facing seat I5 in the port, anda softer material such as copper or lead will adequately provide such aseal.

In normal use, the circulating device is connected in the well tubingstring T by means of the couplings C, and is usually installed justabove a well packer P which is adapted to ,seal between the conductor Tand the well casing-S in the customary manner. It is customary tocompletely fill Vthe well borewith loading fluid when the-drillingoperation-hasA been completed.` The well flow conductor'ortubing T is'Ithen loweredinto the-well' while the-loading fluid is still inthevbore`of the well, as shown in` Figure l, The packer is then 'set and the'loading vfluid in the tubing and in the -bore of the well-below thepacker is then swabbed out in the customary manner. After the packer.'and tubing have been installed, thelcadi'ng uid, suchas water or mud,inthe annular space between-the well casing and the tubing: above thepacker is stored or maintained therein for counterbalancingl thepressure of the fluids .from the well'producing formationacting upwardlyagainst the` lower end of the packer. The column of loadingV fluidapplies a pressure substantially equal to or in excess of the pressureof 'thelluidsfrom the producing formation; and thus reduces theeffective upward force of the formation fluid pressure tendingY tounseal the packer. The plug I6, supported by the reinforcing .sleeve 20,prevents the loading fluid from entering the bore of the tubing throughthe port` I4, "since the seal created by the bushing clamping the llangel1 against the outwardly facing seatv i in the port prevents the loadingfluid from passing lthrough the port. Of course, the loading fluid maybe introduced into the annular space above the packer after the packerhas been installed, if desired,

In practicing the methodv of this. invention however, the loadingfluids'are preferably stored in the annular space between the wellvtubing and casing above the packer in sufficient quantity and of asuniciently heavy consistency to create a load pressure calculated orpredetermined to be substantially adequate to completely kill or preventflow Vof naturalwell fluids fromthe well producing formation if alsovadmitted to the bore of the tubing communicating with the formation.These loading fluids are initially excluded from the tubing by thecirculating device, but are present and in .constant readiness foradmission to the tubing to .prevent flow of fluids from the formationand thereby kill the well. Therefore, it is only necessary to remove thereinforcing sleevey 20 upwardly o-ut of the housing, whereupon thepressure exerted upon the plugs i6 by the loading fluids exteriorly ofthe housing will force the plugs inwardly from the ports, and theloading fluids will be. admitted to the bore of the tubing to kill the'well. Since the quantity and weight of the loadinglluids create a loadpressure considerably; in excess of the natural formation fluidpressure, there will always be a pressure differential acting upon theplugs of the circulating device tending to displace said plugs inwardly;and the strength of the flange on the plugs is sol predetermined that,when the reinforcing sleeve is removed, this differential will beadequate to fracture or shear thev flange yand displace 4the plugs.Thus, the pressures present in the well bore may be utilized to displacetheplugs without the necessity of applying additional extraneouspressure at the well surface.

In order to remove the reinforcing'sleeve, the inner ends of the plugsI6 must be. severed or sheared, Vsince the engagement of the4 inner endsof the plugs in the recesses 22 of the reinforcing sleeve retain thereinforcing sleeve in position in the housing. Obviously, any desired.suitable means may be used for causing upward-movement of thereinforcing sleeve.- Hdwever, it is preferable thatythesleeve-be-displaceable by means utilizing the iluidpressurepresentinthe well. Therefore, thev reinforcing sleeve is illus-v trated as havingan elongate internal annular locking vrecess 23 formedin the upperportion of to force the sleeve upwardly to shear or sever the inner endof the plugs. While other suitableforms of closure devices may be used,it ispref'erable that a device similar to that illustrated in the patentto Herbert C. Otis, No. 2,144,850, dated January 24, 1939, be used.

As clearly shown'in Figure 5, the retrievable closure device consists ofan elongate carrier or mandrel 30- having a cylindrical neck 3l at its;

upper end extending upwardly from a flared or inclined shank 32, whichlater constitutes an expandingelement. The shank extends upwardly from acylindrical head 33 from which a reduced stem 34 depends. The head isslightly smaller in` diameter than the bore of the reinforcing sleeve20, so as to freely slidev thereinto.

A dog supporting collar 35 has a sliding Afit on the neck 3l and isprovided with an undercut annular retrieving flange 36 at its upper end.A plurality of locking dogs 3l having elongate handles 38 are swingablyand slidably. suspended from the lower end of the collar. A retainingcollar 39 is mounted on the upper endof the neck 3l and limits upwardmovement of the collar 35 thereon. An annular stop flange 40 surroundsthe base of the neck, and the handles of the locking dogs extendupwardly through slots in this flange. The flange is providedv with anannular downwardly facing inclined shoulder 4l which is adapted toengage an upwardly facing inclined annular seat 42 at the upper end ofthe bore of the reinforcing sleeve 20 to limit downward movement of thecarrier or mandrel 30 within the sleeve.

The locking dogs have bosses 43 at their lower ends which are arrangedto engage the downwardly facing annular shoulder 23a at the upper end ofthe locking recess 23 when said dogs are expanded by the flared shank 32upon which they are slidable. When the dogs are at thev upper end` ofthe flared shank they are retracted and may enter and be withdrawn fromthe sleeve 2t, but when they are at the lower end of the shank they areexpanded and will engage within the locking recess 23 to preventdisplacement of the carrier upwardly out of the sleeve.

On the reduced'stem 34 a plurality of sealing cups 44 are mounted andheld in spaced relationship by spacer rings 45. The cups are made offabric impregnated with rubber, or other suitable composition, and areslightly smaller in diameter than the'bore of the sleeve 20, wherebythey may readily enter the same. The well pressure fluid entering thebore of the sleeve expands the cups to sealing engagement with the wallof the bore of the sleeve; Two of thesealing cups are shown in positionto seal off fluid pressures from below the device, while the uppersealing cup is turned upwardly and is adapted to seal off pressures fromabove.

A tubular valve cage 4B is screw-threaded onto the lower end of the stem34 and confines the cups and spacer rings between its upper end and thelower end of the head 33. A ball valve 49 is resiliently held in seatingrelationship with the lower end of the stem 34 by a helical spring 5G'48. Openings 5|- permit-well fluid to flow into the bore of the cage toact against the ball valve.

Thus, with the surface iiow controls closed to prevent upward fluidilow, the closure device P may be dropped or lowered into the welltubing until it is positioned in the reinforcing sleeve with the lockingdogs 3l engaging in the recess 23. With the closure device in suchposition, flow of fluids upwardly through the sleeve is prevented and,when the surface flow controls are opened to permit fluid pressure abovethe closure device to escape, the full formation pressure is appliedagainst the under side of the closure device to urge the same upwardly.Since the locking dogs are securely engaged against the shoulder 23a atthe upper end of the recess 23 in the reinforcing sleeve, any upwardforce applied to the closure device will be transmitted to thereinforcing sleeve and such sleeve will be urged or forced upwardly bythe well formation fluid pressure. As the plugs I6 are of a relativelylow shear strength material, they will be sheared or severed when thewell fluid pressure is applied with a sucient differential against theunder side of the closure device P anchored in the reinforcing sleeve.

Once the reinforcing sleeve has been moved upwardly out of the housing,the loading fluid pressure from exteriorly of the housing will fractureor shear the flange Il on the plugs i6 to permit the plugs to bedisplaced from within the ports I4, whereupon the ports will be opened,as shown in Figure 6, and the loading fluids may flow through the portsinto the bore of the well tubing. Since the loading fluids have beenpreviously trapped or stored in the annular space exteriorly of thetubing with calculated or predetermined sufcient quantity and weight tobe 'adequate to kill or prevent flow from the well when admitted to theformation from which flow is conducted through the tubing, it willreadily be seen that the loading fluids will flow through the now openedports to so kill or prevent further flow from the well (see Figure 3).Obviously, if necessary, additional quantities of loading fluids may beintroduced into the annular space at the well surface withoutapplication of high pump pressure.

The closure device may be lowered into the well tubing by means of asuitable wire line lowering mechanism (not shown), the wire linemechanism being removed after the closure device is anchored in thesleeve and before the surface flow controls are opened. It isparticularly desirable that the closure device also be capable of simplybeing dropped into the tubing, whereby it may be quickly inserted inplace in the reinforcing sleeve in case of emergency. In either case,however, the closure device is installed in the reinforcing sleeve andthe reinforcing sleeve is forced upwardly out of the housing by thepressure of the well fluid to permit the ports to be opened withoutmovement of the tubing string or application of pressure from thesurface.

Further, once the reinforcing sleeve has been removed, the plugs arereadily shearable or severable to permit opening of the ports. Since theplugs are preferably formed of a relatively soft low shear strengthmaterial, such as lead, the flange Il may be sheared, severed or brokenoff upon the application of a relatively low fluid pressuredifferential, whereby opening of the ports is positively assured.

It will further be seen that the circulating device is initially closed,but may be readily opened to establish circulation between the bore ofthe tubing and theannular space exteriorly thereof without manipulationor movement of the tubing, and that such a circulating device is adaptedto be installed in the tubing above a packer for establishingcirculation between the annular space above the packer and the bore ifthe tubing.

It will particularly be seen that the circulating device is adapted tobe opened by means utilizing the uid pressures present in the well,whereby manipulation of the tubing is eliminated and it is not necessarythat any supplemental external operating force be employed to move thesleeve and displace the plugs to establish circulation through thecirculating device.

Also, the reinforcing sleeve strengthens the plugs in the circulatingdevice to such an extent that the device will withstand substantially asgreat a pressure from without the flow conductor as will the ilowconductor itself, whereby normal functioning of the flow conductor isnot decreased by the installation of a circulating device. Further, thereinforcing means is releasably held in position and is movable fromreinforcing position to permit the closure plugs to be displaced fromthe port in the circulating device.

It is also manifest that a novel method of treating a well having a flowconductor and a packer therein has been disclosed; wherein a column ofloading fluid, in sumcient quantity and of sufficient weight to preventflow of fluids from the well formation when admitted thereto, is storedin the annular space eXteriorly of the well flow conductor above thepacker and initially excluded from admission into the flow conductor, apath of communication is then established between the annular space andthe bore of the conductor and the loading iiuid is admitted through suchpath to the bore of the conductor for preventing uid flow from the wellproducing formation.

Obviously, the circulating device may be used in installations differingfrom the type already described, and for different purposes. Thus, itImay be used for establishing circulation in either :direction throughthe ports, for circulating loading fluids out of the well, for unloadingfluids from above a packer, and for like purposes. rIhe reinforcingsleeve may be removed from reinforcing position and the plug displacedfrom the port in the manner already described; ory it be so desired, theplug may be displaced outwardly of the port after the sleeve has beenremoved.

Once the plug has been displaced, the port is open to permit circulationof fluids therethrough between the bore of the tubing and the annularspace exteriorly of the housing. The loading fluid in the annular spacemay then be circulated from the bore of the well in the usual manner, oradditional loading fluid may be pumped into the annular space and nowdownwardly therein and through the ports I4 into the bore of the tubing,if desired.

The foregoing description of the invention is explanatory only, andchanges in the details of the construction illustrated may be made bythose skilled in the art, within the scope of the appended claims,without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A circulating device including, a tubular housing having a lateralcirculation port formed therein and an internal stop shoulder below said9 port, a plug fitting said'port initially closing'the same andhaving ashear tip on its inner end,

and a reinforcingsleeve slidable in the bore of formed thereinestablishing communication between the interior and exterior of saidhousing, a closure plug closing said port, a restraining member carriedby the plug and secured in the portfor resisting displacement of theplug from the port, and a' reinforcing4 sleeve slidable in thehousingand supporting the inner end ofthe plug to prevent displacement of saidAplug inwardly from the port, said reinforcing sleeve having a recessin'its exterior surface receiving the inner end of the plug whereby thesleeve is restrained against movement from supporting position, saidplug end being severable upon movement of the reinforcement sleeveupwardly away from supporting position, said sleeve thus being movablefrom supporting position to uncover the inner end of the plug and permitthe plug to be displaced in from` the port, the restraining member beingseverable upon the application of a predetermined fluid pressuredifferential to the plug to permit the plug to be displaced from theport.

3. A circulating device including, a tubular housing adapted to beconnected in a well flow conductor and having a lateral circulation portformed therein establishing communication between the exterior andinterior of said housing, a plug closing said port, releasable meansinitially restraining said plug against displacement from the port, areinforcing sleeve slidable in the housing and having a recess in itsexterior surface for receiving the inner end of the plug to support theplug against displacement inwardly from the port and for restraining thesleeve against movement from supporting position, and upwardly closablefluid pressure actuated valve means removably positioned in the bore ofthe reinforcing sleeve for closing the bore of the sleeve whereby thefluid pressure in the well may be exerted against the valve means tomove the sleeve upwardly away from supporting position and uncover theinner end of the plug, whereupon the plug may be displaced from the portupon application of a predetermined fluid pressure differential theretoto cause release of the releasable restraining means.

4. A circulating device adapted to be connected in a well flow conductorabove a packer for establishing circulation between the interior andexterior of the flow conductor above the packer and including, a tubularhousing having an axial bore and a lateral port establishing a flowpassage between the bore and the exterior of said housing, a closureplug for said port having a shear member secured within the port toinitially restrain the plug against displacement fromy the port, and areinforcing sleeve slidable in the bore of the housing and having arecess in its exterior surface for receiving a portion of the inner endof the plug to support the plug -against upward displacement from theport and for restraining the sleeve against movement from supportingposition, Isaid plug end portion being severable -upon upward-move- -Qment of the sleeve awayjfrom supportingv position to uncover theinnervend-of the plug and permit fluid pressure to be applied againstthe` plug to shear the shear member and displace the vplug from the portto establish communication between the bore-of the conductor andtheexterior thereof fabove the packer.

5. In -a-well flow conductor, acirculating device including, ahousinghaving a lateral circulation port formed therein, a closureplugclosingjsaid port and -having a reduced inner end portion, means onsaidhousing engaging said plug initially restraining saidplug againstdis-- placement outwardly from said port, aY reinforcing sleeve slidablein the housing and havinga recess in its exterior surface receivingaportion of the reduced inner end of the closure plug for restraining thesleeve against upward movement out of the housing and initiallysupporting the plug against displacement inwardly from the port, a-fluidpressure actuatable. closure member; -within the bore of the reinforcingsleeve, said reinforcing sleevehavingvalveseat means adapted to receivesaid closure member whereby the bore of the sleeve is closed againstupward uid iiow and the fluid pressure in the well may be utilized tosever the plug end portion and move the sleeve upwardly away fromsupporting position to uncover the inner end of the plug and permit theplug to be displaced from the port in the housing, whereby communicationmay be established between the interior and exterior of the flowconductor at the circulating device.

6. A circulating device including, a tubular walled body member having apassageway extending from the interior to the exterior of said bodymember wall and forming a. flow port therein, a closure plug closing theport and having a reduced inner end portion, means on the body memberengaging said plug whereby said plug is releasably secured againstoutward displacement from said port, a tubular reinforcing membermovably carried by the body member in slidable engagement with the innersurface of the tubular walls of said body member, said reinforcingmember having a recess in its exterior surface for receiving a portionof the reduced inner end of said plug and supporting the plug againstdisplacement from the port in an inward direction, said plug end portionrestraining the reinforcing member against longitudinal movement in thewalled body member from supporting position, Isaid reduced plug endportion being severable to permit the reinforcing member to move fromsupporting position to uncover the inner end of the plug to permitdisplacement of the plug from the port, and upwardly closable fluidpressure actuated valve means removably positioned within the bore ofthe tubular reinforcing member closable by fluid pressure from below formoving the reinforcing member from plug supporting position to uncoverthe inner end of the plug.

7. A circulating device including, a tubular housing adapted to beconnected in a well flow conductor and having a lateral passagewayformed therein establishing communication between the exterior and theinterior of said housing and providing a circulation port, the outerportion of said port being enlarged to Il provide an outwardly facingshoulder in the port, a closure plug for said port having an annularshear ange fitting in the port with the ange in engagement Vwith theshoulder, a bushing releasably secured in the outer portion of the portsecurely clamping the shear ange against the shoulder in said port torestrain displacement of the plug from the port and to prevent fluidleakage therethrough, a reinforcing sleeve slidable in the bore of thehousing and provided with a recess in its exterior surface adapted toreceive a portion of the inner end of the closure plug whereby thesleeve initially supports the plug against displacement inwardly fromthe port and the end portion restrains the sleeve against displacementfrom supporting position, said reinforcing sleeve bore having valveseating means, a uid pressure actuated closure member in said sleevebore engageable with said valve seating means for closing the bore ofthe sleeve against upward low whereby the uid pressure in the well maybe utilized to move the sleeve upwardly away from supporting position,said closure plug end portion being severable to permit the sleeve to bemoved from such supporting position and to uncover the inner end of theplug, whereupon the shear ange on t-he 12 plug may be sheared upon theapplication of a predetermined fluid pressure differential to the plugend to permit the plug tov be displaced from the port.

8. A circulating device of the character set forth in claim 7, whereinthe housing is provided with a plurality of radially spaced lateralcirculation ports and plugs and the reinforcing sleeve is provided witha recess in its exterior surface for receiving the inner end portion ofeach of said plugs.

IRA A. MILLER.

References Cited in the le of this patent UNITED STATES PATENTS NumberName v Date 1,579,141 Pierce Mar. 30, 1926 1,912,578 Halliburton June 6,1933 2,058,825 Rallet et al. Oct. 27, 1936 2,144,850 Otis Jan. 24, 19392,185,522 Rollins Jan. 2, 1940 2,307,662 Baylor Jan. 5, 1943 2,343,076Otis et al Feb. 29, 1944 2,393,404 Otis Jan. 22, 1946 2,397,473 CrowellApr. 2, 1946

